Comment 6 for bug 1970074

Another occurrence:

[4.410322] =========================================================
[4.410323] UBSAN: array-index-out-of-bounds in /build/linux-hwe-5.15-scdIe0/linux-hwe-5.15-5.15.0/drivers/ata/libahci.c:968:41
[4.410326] index 15 is out of range for type 'ahci_em_priv [8]'
[4.410327] CPU: 1 PID: 434 Comm: scsi_eh_6 Tainted: G OE 5.15.0-33-generic #34~20.04.1-Ubuntu
[4.410330] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./B550M-HDV, BIOS P2.10 02/24/2022
[4.410331] Call Trace:
[4.410332] <TASK>
[4.410334] dump_stack_lvl+0x4a/0x5f
[4.410339] dump_stack+0x10/0x12
[4.410340] ubsan_epilogue+0x9/0x45
[4.410342] __ubsan_handle_out_of_bounds.cold+0x44/0x49
[4.410344] ahci_qc_issue+0x15e/0x160 [libahci]
[4.410348] ata_qc_issue+0x132/0x240
[4.410351] ata_exec_internal_sg+0x2c6/0x580
[4.410353] ? vprintk_default+0x1d/0x20
[4.410356] ata_exec_internal+0x67/0xa0
[4.410358] ? sata_scr_read+0x45/0x60
[4.410360] sata_pmp_read.isra.0+0x8a/0xb0
[4.410363] sata_pmp_read_gscr+0x40/0xa0
[4.410365] sata_pmp_attach+0x8b/0x530
[4.410367] ata_eh_revalidate_and_attach+0x249/0x490
[4.410369] ata_eh_recover+0x6d5/0x1370
[4.410371] ? ahci_stop_engine+0xb0/0xb0 [libahci]
[4.410373] ? ahci_do_hardreset+0x150/0x150 [libahci]
[4.410376] ? ahci_do_softreset+0x260/0x260 [libahci]
[4.410378] ? ata_phys_link_offline+0x60/0x60
[4.410381] ? ata_phys_link_offline+0x60/0x60
[4.410382] sata_pmp_eh_recover+0x61c/0xa80
[4.410385] ? ahci_stop_engine+0xb0/0xb0 [libahci]
[4.410387] ? ata_phys_link_offline+0x60/0x60
[4.410389] ? ahci_do_softreset+0x260/0x260 [libahci]
[4.410391] ? ahci_do_hardreset+0x150/0x150 [libahci]
[4.410394] sata_pmp_error_handler+0x23/0x30
[4.410396] ahci_error_handler+0x43/0x80 [libahci]
[4.410398] ata_scsi_port_error_handler+0x3a0/0x850
[4.410400] ata_scsi_error+0x9c/0xd0
[4.410402] scsi_error_handler+0xc3/0x520
[4.410404] ? scsi_eh_get_sense+0x250/0x250
[4.410406] kthread+0x127/0x150
[4.410408] ? set_kthread_struct+0x40/0x40
[4.410410] ret_from_fork+0x1f/0x30
[4.410413] </TASK>
[4.410414] =========================================================